Dominion’s Plant May Have Exceeded Limits in Quake, NRC Says

By Brian Wingfield -
Aug 29, 2011

A Dominion Resources Inc. nuclear
power plant in Virginia may have been subjected to ground motion
greater than it was designed to withstand in last week’s
earthquake, the Nuclear Regulatory Commission said.

Dominion notified the agency that a review determined
shaking from the 5.8-magnitude temblor “may have exceeded”
design limits of the North Anna Power Station, the agency said
today in an e-mailed statement. The NRC sent additional
inspectors to the plant to assist agency officials in their
investigation, the agency said.

The North Anna plant, about 40 miles (64 kilometers)
northwest of Dominion’s Richmond headquarters, has been shut
since the Aug. 23 earthquake. Dominion is gathering data on the
event and its effect on the plant, Jim Norvelle, a Dominion
spokesman, said today in an e-mail.

“Dominion needs to do more analysis to determine how a
quake of that strength could affect the plant’s ability to
safely shut down,” Scott Burnell, an NRC spokesman, said in an
e-mail.

Dominion is analyzing data and reports may not be completed
until the end of the week, Norvelle said.

“In multiple inspections, we have not found significant
damage,” he said. Some insulation was shaken from pipes during
the earthquake, according to Norvelle. “All safety systems
operated as designed and built,” he said.

Seismic, Structural Experts

The nuclear agency said a seismic expert and a structural
engineer were sent to the plant after the earthquake. Technical
experts will join agency officials at the plant to help the NRC
collect information on the effect at North Anna and to help
assess earthquake risks at U.S. nuclear reactors.

The addition of NRC experts “should not be interpreted to
mean that Dominion staff responded inappropriately or that the
station is less safe as a result of the quake,” said Victor
McCree, the agency’s regional administrator, said in the
statement.

Dominion isn’t disclosing when the plant may start
generating electricity because such market-sensitive information
may affect electricity prices, Norvelle said.